/** 合同打印弹窗：HTML → DOCX 预处理与生成 */

import { Buffer } from 'buffer'

const DOCX_MIME = 'application/vnd.openxmlformats-officedocument.wordprocessingml.document'

type HtmlToDocxFn = (
  htmlString: string,
  headerHTMLString?: string | null,
  documentOptions?: Record<string, unknown>,
  footerHTMLString?: string | null
) => Promise<Blob | ArrayBuffer>

/**
 * html-to-docx（含 browser 包）在 Vite 二次打包后仍会直接读全局 Buffer/global。
 * 必须在调用转换前注入，否则 buildImage 报 Buffer is not defined，随后 global is not defined。
 */
function ensureDocxNodeGlobals(): void {
  const g = globalThis as typeof globalThis & {
    Buffer?: typeof Buffer
    global?: typeof globalThis
    process?: { env?: Record<string, string | undefined> }
  }
  if (!g.Buffer) g.Buffer = Buffer
  if (!g.global) g.global = g
  if (!g.process) g.process = { env: {} }
  else if (!g.process.env) g.process.env = {}
}

/**
 * 懒加载 browser 构建。
 * Vite 默认会解析到 Node ESM（依赖 Buffer/global）；显式 browser 入口 + 上方 globals 注入。
 */
async function loadHtmlToDocx(): Promise<HtmlToDocxFn> {
  ensureDocxNodeGlobals()
  // 经 vite alias 指向 browser.esm.js
  const mod = await import('@turbodocx/html-to-docx')
  const candidate = typeof mod === 'function' ? mod : (mod as { default?: unknown }).default
  if (typeof candidate !== 'function') {
    throw new Error('html-to-docx 加载失败：未获得可调用的转换函数')
  }
  return candidate as HtmlToDocxFn
}

function arrayBufferToBase64(buffer: ArrayBuffer): string {
  const bytes = new Uint8Array(buffer)
  let binary = ''
  const chunk = 0x8000
  for (let i = 0; i < bytes.length; i += chunk) {
    binary += String.fromCharCode(...bytes.subarray(i, i + chunk))
  }
  return btoa(binary)
}

async function urlToDataUrl(url: string): Promise<string | null> {
  try {
    const res = await fetch(url)
    if (!res.ok) return null
    const blob = await res.blob()
    const buf = await blob.arrayBuffer()
    const mime = blob.type || 'application/octet-stream'
    return `data:${mime};base64,${arrayBufferToBase64(buf)}`
  } catch {
    return null
  }
}

/**
 * 将 HTML 中非 data: 图片先转成 data URL，避免库内 Node Buffer 路径失败导致印章/水印丢失。
 */
export async function inlineRemoteImagesAsDataUrls(html: string): Promise<string> {
  const srcRe = /\bsrc=(["'])([^"']+)\1/gi
  const urls = new Set<string>()
  let match: RegExpExecArray | null
  while ((match = srcRe.exec(html)) !== null) {
    const url = match[2]
    if (url && !url.startsWith('data:')) urls.add(url)
  }

  if (!urls.size) return html

  const replacements = new Map<string, string>()
  await Promise.all(
    [...urls].map(async (url) => {
      const dataUrl = await urlToDataUrl(url)
      if (dataUrl) replacements.set(url, dataUrl)
    })
  )

  if (!replacements.size) return html

  return html.replace(/\bsrc=(["'])([^"']+)\1/gi, (full, quote: string, url: string) => {
    const dataUrl = replacements.get(url)
    return dataUrl ? `src=${quote}${dataUrl}${quote}` : full
  })
}

/**
 * 将已预处理的合同 HTML 转为 DOCX Blob（浏览器下载用）。
 * 调用方须先执行 prepareContractHtmlForDocx。
 */
export async function generateContractDocxBlob(
  preparedHtml: string,
  title?: string
): Promise<Blob> {
  ensureDocxNodeGlobals()
  const HTMLtoDOCX = await loadHtmlToDocx()
  const htmlWithImages = await inlineRemoteImagesAsDataUrls(preparedHtml)
  const fullHtml = `<!DOCTYPE html><html><head><meta charset="UTF-8" /></head><body>${htmlWithImages}</body></html>`
  ensureDocxNodeGlobals()
  const result = await HTMLtoDOCX(fullHtml, null, {
    orientation: 'portrait',
    title: title || '合同',
    margins: {
      top: 720,
      right: 720,
      bottom: 720,
      left: 720
    }
  })

  if (result instanceof Blob) return result
  return new Blob([result as ArrayBuffer], { type: DOCX_MIME })
}

export function parseContractSupplierCode(contractNo?: string | null): string {
  if (!contractNo) return 'SX'
  const match = String(contractNo).match(/^([A-Z]+)\/X-JT/)
  return match?.[1] || 'SX'
}

export function stripContractLogoHtml(html: string): string {
  let result = html.replace(/<div[^>]*>\s*<img[^>]*(?:logo\.gif|logo)[^>]*>[\s\S]*?<\/div>/gi, (match) => {
    if (match.includes('logo.gif') || match.includes('/logo') || (match.includes('logo') && !match.includes('watermask'))) {
      return ''
    }
    return match
  })
  result = result.replace(/<img[^>]*(?:logo\.gif|logo)[^>]*(?![^<]*watermask)[^>]*>/gi, '')
  return result
}

export function toAbsoluteAssetUrls(html: string, origin: string): string {
  const base = origin.replace(/\/$/, '')
  return html.replace(/\bsrc=(["'])(\/[^"']+)\1/gi, (_m, quote: string, path: string) => {
    return `src=${quote}${base}${path}${quote}`
  })
}

export function injectSxWatermarkHtml(html: string, watermarkUrl: string): string {
  const watermarkBlock = `<div style="text-align:center;margin:8px 0 16px;">
  <img src="${watermarkUrl}" alt="水印" style="width:50%;max-width:400px;opacity:0.15;" />
</div>`
  return `${watermarkBlock}${html}`
}

export function prepareContractHtmlForDocx(options: {
  html: string
  contractNo?: string | null
  origin: string
}): string {
  const origin = options.origin.replace(/\/$/, '')
  const supplierCode = parseContractSupplierCode(options.contractNo)
  const isSX = supplierCode === 'SX'

  let html = options.html || ''
  if (!isSX) {
    html = stripContractLogoHtml(html)
  }

  html = toAbsoluteAssetUrls(html, origin)

  if (isSX) {
    html = injectSxWatermarkHtml(html, `${origin}/watermask.jpg`)
  }

  return html
}

export function buildContractDocxFileName(
  contractName?: string | null,
  contractNo?: string | null
): string {
  const raw = (contractName && String(contractName).trim()) || (contractNo && String(contractNo).trim()) || '合同'
  const safe = raw.replace(/[/\\:*?"<>|]/g, '-')
  return `${safe}合同.docx`
}